The present invention is directed to bumpers of the type used on trucks. Such bumpers which are of especially heavy construction are mounted on the front of the truck, extending thereacross, to protect the truck frame and body from damage on impact with another object. Additionally, the ends of the bumper extending across the front of the front wheels serve as guards against rocks and small objects picked up by the front wheels being thrown forwardly into oncoming traffic.
A problem has arisen on various occasions with disastrous results occurring when a truck collides with another object, bending the end of the bumper backwardly against the front tire. When this occurs the bumper snags or locks against the tire causing loss of steering control and turning what might have been only a minor mishap into a major accident. Two patents which have recognized and are directed to this problem include U.S. Pat. Nos. 3,596,963 and 3,843,180.
U.S. Pat. No. 3,596,963 to Phillips in directed to an elongated bumper extension of the type made of a frangible material which does not bend but breaks and falls away on impact. The patent to Alexander, U.S. Pat. No. 3,843,180 is directed to a pivotal bumper extension which is hinged to the main portion of the bumper such that it pivots forwardly or rearwardly on impact, then automatically springs back to a normal bumper position. There are other patents of this type, some of which return to a normal position after impact and others utilizing shear pins or the like which permit the bumper extension to fall away on impact.
However, these devices lend themselves to new problems and deficiencies. Firstly, the hinged extensions do not serve to provide protection as a bumper for the frame or truck body due to the spring pressure of the mechanism which absorbs little, if any, impact. Therefore, the brunt of the impact must be absorbed by the truck or the truck tire which can cause blowouts. Secondly, if the extensions are of the type which shear or otherwise break away, there is a need for replacement, perhaps frequently and expensively. Also, without any bumper at all in front of the tire the truck might climb upon and crush cars involved in the accident.
Thus it can be seen that while the use of bumper extensions of hinged or breakaway type is broadly old, there remains a need for a bumper extension which is sufficiently strong to act as a permanent bumper to protect the truck frame and body by absorbing impact; yet of a structure preventing the snagging of a wheel and consequent loss of steering control in cases where the impact is strong enough to bend the bumper back into the tire.